


Underworld

by haithuong313



Category: Persona 5
Genre: Age Difference, Aged-Up Character(s), Alternate Universe, Angels, Demons, I don't even know if I could do this help, M/M
Language: English
Status: In-Progress
Published: 2018-09-03
Updated: 2018-09-03
Packaged: 2019-07-06 13:57:51
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,155
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15887424
Author URL: https://archiveofourown.org/users/haithuong313/pseuds/haithuong313
Summary: It is not common knowledge amongst human that other societies exist outside of their own. Humans have always thought of themselves as the center of the universe, the top of the food chain, the rulers of this planet, and everything is either to be conquered by them, or serve their greed and desire. They are completely oblivious to the fact that they themselves are just a link in the food chain, that their own society is being manipulated by a higher society in the shadows, by predators called Demons.





	Underworld

**Author's Note:**

> Thank you [Mewchan](https://tmblr.co/mH88zsQeLpyD-sxkzJxN_OA), for discussing with me about this idea and also translate this bunch of words for me. And everything else too.
> 
> Thank you @[lod](https://archiveofourown.org/users/lod/pseuds/lod), for reading and beta this fic for me, so that I could finally share it with the world. You are always almighty.

“Welcom—”

Iwai turns his chair toward the door to greet the new customer as the doorbell rings, but goes silent immediately when the smell of cigarette reaches his nose. He is not too unaccustomed to that reeky burned smell; hell, he can even tell what brand it is just from the smell. _Midnight dream_ , strong and passionate, yet unpredictable like a midsummer dream—definitely not for peasants, but not sophisticated enough to be called high class. Though, it cannot be found in any store in Tokyo, nor in any store in this country—not in any place on the Surface. That is why Iwai has to be on high alert. 

It is not common knowledge amongst human that other societies exist outside of their own. Humans have always thought of themselves as the center of the universe, the top of the food chain, the rulers of this planet, and everything is either to be conquered by them, or serve their greed and desire. They are completely oblivious to the fact that they themselves are just a link in the food chain, that their own society is being manipulated by a higher society in the shadows, by predators called _Demons_. Demons are not the only ones who prey on human, but that is none of Iwai’s concern. Right now, he just needs to think of some way to deal with the demon that has just appeared at Untouchable’s doorstep.

Why does he know about all that? It is simply because he used to be one of them—a dweller of the Underworld. Well, a resident, yes; but one of them? Never. He has never forgotten the cold, ostracized gaze he faced wherever he went, like the word “outcast” was branded on his chest. Actually, life there was not too bad; the condition was far superior compared to Tokyo—much cleaner air and way less cluttered constructions. However, it was just neither a place for him, nor a place to raise a human child. Yes; at thirty-two human years old, Iwai is now a father, though not by normal way, but it is something that he wanted. Iwai left a lot behind at his birthplace, including memories and his own past self; but there is one thing that he will carry with him to his death—his stubbornness, the thing that brings to him way more trouble that it should, but has also helped him survive till this day.

“Didn’t I already tell you, Tsuda? I will never return to that place. I have never cared about the ‘main affair’ and never will.”

Iwai speaks coldly, not even bothering to stand up from his seat to greet the man, even though from the look, he is just like a usual yakuza boss, with several lackeys behind his back.

“C’mon, don’t act like I’m a troublesome salesman. Especially when you’re the salesman ‘ere, Iwai. Would it hurt ye to give yer customer a warm welcome, eh?"

Iwai sighs, quietly stands up and goes to the storage room. Outside, Tsuda lets out a wide grin. He is not the only one who came here for a bargain with Iwai, but every single one of them was scared out of their wits by him. The reason that Tsuda can still set foot into this store is because they used to be “friends”, even though they were not exactly on good term. Tsuda had always been a hotheaded one, and he was not fond of Iwai’s background. However, Iwai still keeps contact with some from the “family” out of obligation, but only stops at business relationship. He still needs this airsoft store to make ends meet, after all.

Quite surprisingly, after buying some of the items in stock, Tsuda does not bother Iwai any further. He had not expected the guy to let him go anytime soon. 

“Hey, look where ya going, kiddo!” Tsuda shouts, as if a child just stuck chewing gum on his new suit.

“…" 

“Ya still dare to look at the boss?”, one of the lackeys growls.

“Sorry…” The teenager lets out a barely audible apology.

“Damn brat… Yer eyes makes me itch!!”

Tsuda screeches, causing the young boy to curl up as if he were about to take a punch. But Iwai has appeared before Tsuda can send him flying into a nearby pile of trash.

“I didn’t think ye demons sunk that low these days, bullying a kiddo like that.” Iwai lets out a sigh.

“What did you say?! Basta—”

“My point is, I gotta ask ya to let him go. He’s a part-timer ‘ere.”

“Fineee, I’ll let it slide just because ya ask. Ya _owe_ me one, Iwai.”

Iwai rolls his eye. _Like a true demon._ Tsuda and his lackeys quickly leaves the back alley of Shibuya, and the boy runs straight into the store, like if he has to stand outside the place for one more minute he will be snatched by another demons.

“Ain’t you a trouble magnet or something? Can’t you just stay still and not give me any more headaches?”

“It was him who bumped into me, didn’t you see that?” The raven-haired teenager murmurs under his breath, clumsily hiding annoyance under his voice. His eyes blocked from view by black-framed hip glasses, presumably to keep people from reading his expression, but to Iwai that looks more silly than mysterious.

“Doesn’t mean you should provoke him, don’t you see his _tattoo_?”

Iwai himself has a tattoo on his neck, so he doesn’t assume people who has tattoo belongs to the yakuza, but the “tattoo” that he mentioned is a completely different thing. It is more like markings, that only Iwai and the boy can see, invisible to the normal eyes. The boy sighs, putting his school bag aside, hands scrubbing over his shoulder where Tsuda bumped into him. He turns his head toward Iwai, grey eyes peeking out under black glasses.

“Yup, a _strong_ one. Totally my taste. So I just give him a good look, and he acts like he wanna kill me on the spot. Such a turnoff.”

The boy directs his gaze toward Iwai, grey flickering under raven locks of hair. Small tongue suggestively licking his lower lip. These smooth, plump lips, that make one just want to bite and suck on them until they become all swollen red. And then surrender oneself to the delightful taste of lust, giving up the last shred of reason.

In the flash of an eye, he wraps his arms seductively around Iwai’s neck, locking their gazes together. The scent of the boy’s slender neck and collarbones under his half-opened white collar sneaks into their breath, like a deadly poison that immobilizes anything it touches. A merry hunt.

“That’s enough.”

With a deadpan expression, Iwai pushes the boy’s face away. Even with that much pheromone, he does not seem to be affected at all.

“If you try that again, I’ll toss you to Tsuda and his friend, got it? Don’t try to test my patience, _Akira Kurusu_. There’s a lot of work needs to be done here, and I don’t remember hiring a whore.”

“Don’t be a prude, Iwai-san!”

Fortunately, Iwai is able to stop him before he can even start licking his hands. He shudders when thinking of that scenario, cannot bring himself to imagine what would happen if someone happened to walk in the store right then.

Now, when it is just the two of them, Akira does not hesitate to show his true form. Normal humans would probably only see an ordinary teenager with curly black hair wearing a silly pair of glasses, but what Iwai sees is a demon with beastly eyes and fangs, claws sharp as knives, and black tail swinging freely in midair, its pointy tip shaped like a small spearhead. His tattoos also surface—ghastly blue patterns imprinted on his cheeks, like the stripes of a lynx. _A true demon_.

“Tsuda is strong, but how could he measure up to you, Iwai-san?” Akira creeps closer again, along with a surge of magic as strong as a hurricane, hungrily waiting to drown Iwai in lust. And yet the man still doesn’t move for even an inch. “I only want _Iwai-san_.”

“Just give it up, I’m a _human_ now. Everyone treated me like shit back in Underworld, and I swear no demon would want to stick with a halfling like me. If that’s ‘strong’ in your book, you succubi sure have strange taste.”

“Well, maybe you are a _demi-human_ , but for a demon as strong as Tsuda to come here for you, there must be something interesting about you…”

Akira narrows his eyes, looking at Iwai questioningly. He always finds an excuse to hang around this place because of his curiosity about Iwai, but the man has never revealed anything about his life back in Underworld. On the Surface, bound by rules and customs, Iwai Munehisa just seems like a single father with a dark past, willing to do anything for his little son’s future. The majority of the demons who live on the Surface, like Iwai and Akira, blend in with human society by mimicking their friendly and courteous manners. Only in Underworld do their disguises unravel; it is the place where their true self is nurtured, where generations of their ancestors have settled and built a paradise for their species.

“The day will surely come when I am able to see you in your true form in Underworld. The demon whose strength surpasses all others’, who rivals even the Demon King. And then… I will place a spell on you, to make you _mine, and mine alone_. And I will be the ruler of Underworld.” 

Akira smiles, pushing his glasses up with a satisfied grin, as he contemplates this “totally plausible” outcome. Iwai looks at him wide-eyed.

“I’m sure you can do it. But right now, this place needs sweeping.” Iwai throws a duster right into Akira’s wicked face. 

*** 

Everything all started around a month ago, when Kaoru got home with yet another low score on his English exam. The boy had fearfully handed over his test result for Iwai to check and sign, as if his father would suddenly turn into a scary fiend. Iwai had never laid a hand on Kaoru; in fact, Kaoru had always been an obedient child—he never cried loudly or demanded gifts, and didn’t even complain when he was bullied in kindergarten for the scar on his neck. In any case, Iwai had promised himself he’d never treat his son the way his violent drunkard of a father had.

No, Kaoru wasn’t afraid of Iwai; what he was afraid of was of being a burden. He knew that Iwai taking on the responsibility to raise him—the child who was unwanted from the start—was totally from the kindness of his heart, and he wasn’t sure that he deserved it. Kaoru knew that all the expenses and monthly bills, all the responsibilities of parenting took all of Iwai’s time. He didn’t want to… no, he _must_ not let himself be just one more burden that Iwai had to bear, because then Iwai might realize that his decision to take him in was a mistake.

Iwai, on the other hand, was completely unaware of Kaoru’s fears, simply because he had never thought of him as a burden. To Iwai, Kaoru had just always been a gentle, even timid child. He still remembered the first time he’d taken Kaoru to the run-down apartment that he’d somehow managed to get for them. The boy hadn’t shown joy or even disgust, only looked around with shy eyes and replied to every one of Iwai’s questions with “Yes…”, “Whatever is fine.”

When he was finally able to afford a place big enough for Kaoru to have his own room, the kid had trouble getting to sleep in the strange new place. However, he didn’t dare to wake Iwai up; he only found out when he heard sobbing behind the closed bedroom door. At Kaoru’s age, Iwai was already familiar with every nook and cranny of the slums, eating and sleeping on the street on a daily basis, so he didn’t really understand the kid’s sensitivity, but that was even more of a reason to want to protect him.

Iwai told Kaoru that he needed to go to night class, because he himself couldn’t even write past the basics, nevermind tutoring him. But Kaoru flat out refused to go, insisting that he could read from the textbook by himself, despite Iwai using his stern voice to make him listen. As stubborn as a certain someone. Iwai worried over it for a whole week, until Kaoru suddenly brought home another boy that he called “senpai” one day, who had promised to tutor Kaoru for free.

At first glance, he was just an ordinary college student, with curly black hair and black-framed glasses that covered almost half of his face.

“I’m Akira Kurusu, nice to meet you,” the boy humbly introduced himself with a gentle yet charming smile.

A remarkably pretty boy; even Iwai, who rarely gave out compliments, had to admit it. His style was simple yet refined; he wore a smooth black vest with a silver pin on the neatly folded collar, revealing his masculine frame while still looking prim and proper. Akira had an aristocratic look to him, like he came from a cultured lineage.

“Iwai-san, please let me help with the cooking,” Akira offered while Iwai was in the kitchen preparing dinner. The boy’s offer surprised him, but he didn’t refuse. Even more surprisingly, he was an unexpectedly quick and adept learner.

“Thank you so much for helping Kaoru. Not only is his English greatly improving, but he also looks much more confident than he used to.” Iwai started the conversation while Akira was tasting the soup. It was a genuine compliment—Iwai had never seen Kaoru opening up to someone and laughing freely like that with anyone before. Akira seemed to have some strange energy that drew people to him.

“I think Kaoru learned the most from _Iwai-san_ though. He would never give up no matter how hard the problem he faced was.” Akira was smiling, but his words seemed deliberately chosen, hiding his real emotions.  “Even though Kaoru may look timid on the outside, inside his spirit is strong.”

“I don’t think ‘strong’ is the best way to describe it, more like ‘stubborn’. But hey, you seem to know a lot about me, considering this is the first time we talk?”

Akira gave Iwai a curious look. “Kaoru told me a lot about you during our lesson. He’s really proud of his father.”

Iwai studied Akira for a while, his intense gaze causing Akira to look down shyly.

“I don’t want to make you feel uneasy, especially after you’ve spent so much time helping my son. But you can’t slip past my eyes.”

“…Iwai-san?”

“Your little human act’s quite impressive for a greenhorn, but it’ll take more than that to fool me, _demon_.”

Iwai could see Akira being spooked for a second, but trying his best to keep his composure.

“You’re right, but… that’s not why I’m here. It’s true that a lot of demons want to cause harm to humans, but some of us just want to live our lives without bothering anyone. Iwai-san is one of them too, right?” Akira tried his best to explain. “We’ve lived in peace with humans for a long time…”

Iwai’s expression didn’t change, still looking at Akira with a questioning gaze.

“This isn’t the first time a demon’s tried to contact me. I know what you want, so don’t even bother trying.” 

Behind his glasses, his grey eyes changed expression, from calm and collected to a raging storm. However, the storm was still not breaking out. Iwai didn’t want to scare Akira. He knew that every demon that tried to contact him always had an ulterior motive, but Iwai had never met someone like Akira. It wasn’t just his courteous, humble manner, or his charismatic way of speaking, but also the well-hidden mystery he could glimpse deep in those grey eyes. Iwai had lived too long with demons to be deceived by the greedy look of those who came to see him. He could see it no matter how many lies they tried to covered it up with. However, he saw none of that in Akira.

Akira turned toward the pot of soup with a slump in his shoulders. Iwai felt something weighing down in his chest all of a sudden—he couldn’t bring himself to speak harshly to Akira. Whatever his reasons, he didn’t actually think Akira intended to put Kaoru in harm’s way, not after all he’d done to help. Even so, it would be better to end it now than to risk trouble arising in the long run, he thought. No matter what Akira’s goal was, he had to affirm that he would not accomplish it in this place. 

“But… Kaoru still needs a tutor, right?” Akira said quietly.

Iwai let out a long sigh. Well, he was the one in a tight spot here. If he scared Akira away, Kaoru would hate him, even if he wouldn’t say so outright. Moreover, he would certainly not go to night class even if Iwai insisted, and they would have to worry about his grades again. 

Resigned, Iwai said, “I’ll pay you for the tutoring; I don’t want to be in your debt. But about that other thing you want me to do, sorry, the answer will always be no.” 

Akira sighed, probably relieved that Iwai had decided not to kick his ass out of the house. _So, the matter is resolved_ , Iwai thought. Looking over at the teenager, he felt a bit regretful for pushing Akira away before their friendship could even start.

“I… I don’t need money.”

“Huh?”

Akira extended his hand. Long, slender fingers brushed against Iwai’s wrist, gently stroking the rough skin. Iwai was at a loss of words, unable to understand what Akira intended to do. He tilted his head up to look at Iwai, lips curled into a smile that seemed out of place on his pretty face. It was neither the pure, shy smile he’d shown before, nor an angry or wicked smile. This smile was enigmatic and dangerous, as if Iwai had walked into the lair of the demon kings at the center of Hell, and the gate had slammed shut behind him with an ominous creak.

“You can do something _else_ to pay me back.”

Iwai heard the whisper of beasts in the howling wind.

_A succubus._

  


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NOTE

` Hell, I created a whole Universe for this fic and it is so big I don't even know if I could sum it up. So read at your own risk •́ ͜ʖ •̀`

`Meet me on [Tumblr](https://greenieartblog.tumblr.com/)`

`Also here is a little concept art `

``


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